Hello! I'm thinking of having one this year. I've just started to pin ideas, and have found some inspiration from the movie Practical Magic - like a sisterhood theme. Pier 1 has some cute party decorations like straws that have paper cutouts that say, "Drink up Witches" and I like the idea of delivering cheap dollar store hats and asking guests to decorate them. There was a thread here years ago I've been trying to find from someone who had great ideas-maybe you? 
http://www.pier1.com/on/demandware.store/Sites-pier1_us-Site/default/Search-Show?q=Witch
http://www.pier1.com/on/demandware.store/Sites-pier1_us-Site/default/Search-Show?q=Witch